The present invention relates to methods of producing radiation and to radiation-producing apparatuses and, in particular, to a radiation-producing apparatus used to deactivate microbial contamination.
The United States Postal Service has been used as a mode of delivery for anthrax spores. The potential exists for the Postal Service and other courier services to be used for the delivery of other biological agents.
Paper envelopes are relatively porous to finely divided spores. In the normal handling and processing of mail, anthrax spores and other biological materials can escape from envelopes contaminating the surfaces of mail handling equipment, adjacent floors and equipment, the exterior of the carrier envelope and the surfaces of other envelopes.
A need exists for a means for immediate on-location sterilization of suspicious mail and the surfaces of other mail and processing equipment with which the suspicious mail has come into contact.
Liquid and spray sterilants are effective for deactivating microbes on hard surfaces of mail processing equipment, but are incompatible with paper envelopes and washable inks. Further, full sterilization with liquids may require shutting down mechanical equipment or even partially disassembling it. Subsequent to sterilization with a liquid, re-lubrication of cleaned surfaces may also be required.
Plasma discharge methods are effective for surface sterilization. However, plasma discharge is not effective for treating spores or other microbes in the interior of an envelope.
Toxic gases such as ethylene oxide, ozone gas and other gaseous sterilants are also effective for deactivating microbes. However, because the sterilant gases are also potentially harmful to humans, they are typically used in a sealed environment. Creating a sealed environment around a large piece of mail processing equipment is time-consuming and disruptive to mail handling processes. Due to a relatively slow penetration rate, treatment of a piece or bundle of suspicious mail by this method can be relatively time-consuming.
High energy radiation is also effective for deactivating microbes. However, high energy radiation systems tend to be large and bulky. They are typically difficult to move from place-to-place. Moreover, the high energy radiation raises shielding issues regarding the protection of workers from radiation, stray or otherwise. Furthermore, high energy radiation dissipates a large energy into the target, i.e., the envelope and microbial material, that leads to heating of the microbial material, as well as the envelope. This heating increases the probability that the envelopes will break and spill microbial material. High energy radiation can cause sufficient heating to ignite paper envelopes and any combustible contents.
The present invention provides a portable radiation-producing apparatus capable of deactivating spores such as, but not limited to, anthrax spores, other infectious, biological contamination and will be described with particular reference thereto. It is to be appreciated, however, that the present invention will also find utility in the radiation treatment of surfaces and materials for other purposes, such as: to initiate chemical reactions; to effect cross-linking in thermosetting, polymeric systems; to effect cross-linking in non-curing polymeric systems; and, to decontaminate thin objects such as letters or money and the like. The invention is also applicable for treating surfaces in hospitals, food service facilities, food processing facilities and other environments in which surfaces are subject to biological contamination.
The present application provides a new and improved irradiation apparatus.
In accordance with one aspect of the present invention, there is provided a radiation-producing apparatus for producing electron beam radiation and X-ray beam radiation. The radiation-producing apparatus is comprised of a radiation generating device, a pulsed high voltage generator and a control system that selectively controls the transfer of energy from the pulsed high voltage generator to the radiation generating device. The radiation-producing apparatus includes a cathode and an anode, the anode being spaced apart from the cathode, a pulsed high voltage generator that produces an electric field between the cathode and the anode, that leads to the formation of a pulsed plasma that surrounds the cathode, and a control system. The electrons of the pulsed plasma that initially surround the cathode, are accelerated toward the anode.
In accordance with another aspect of the present invention, there is provided a radiation-producing apparatus, comprised of a radiation (electron beam and X-ray beam) generating device, a pulsed high voltage generator and a control system. The pulsed high voltage generator is comprised of a power source and a Tesla resonant transformer. The Tesla resonant transformer has at least one capacitor, a primary coil, a secondary coil and a plurality of capacitors forming a capacitor bank. The capacitor bank is disposed axially within the secondary coil. The pulsed high voltage generator is connected to the radiation generating device for providing electrical energy to the radiation generating device. The control system is connected to the pulsed high voltage generator for selectively controlling the transfer of energy from the pulsed high voltage generator to the radiation generating device. The radiation-producing apparatus generates pulsed beams of electrons and X-rays. Each pulse of the beam has a time duration of about 100 nanoseconds or less.
In accordance with another aspect of the present invention, there is provided a radiation-producing apparatus, comprised of a radiation generating device, a pulsed high voltage generator and a control system. The pulsed high voltage generator is comprised of a power source and a Tesla resonant transformer. The Tesla resonant transformer has at least one first capacitor, a primary coil, a secondary coil and a second capacitor. The second capacitor is disposed axially within the secondary coil. The pulsed high voltage generator is connected to the radiation generating device for providing electrical energy to the radiation generating device. The control system is connected to the pulsed high voltage generator for selectively controlling the transfer of energy from the pulsed high voltage generator to the radiation generating device. The radiation-producing apparatus generates pulsed beams of electrons and X-rays. Each pulse of the beam has a time duration of about 100 nanoseconds or less.
In accordance with another aspect of the present invention, there is provided a radiation-producing apparatus, comprised of a radiation generating device, a pulsed high voltage generator and a control system. The electron beam generating device is comprised of an anode separated from a cathode to form a gap therebetween. The anode may be made of copper foil, a copper foil film, tantalum, tungsten or a combination thereof. The pulsed high voltage generator is comprised of a power source and a Tesla resonant transformer. The Tesla resonant transformer has at least one capacitor, a primary coil, a secondary coil and a plurality of capacitors forming a capacitor bank. The capacitor bank is disposed axially within the secondary coil. The pulsed high voltage generator is connected to the radiation generating device for providing electrical energy to the radiation generating device. The control system is connected to the pulsed high voltage generator for selectively controlling the transfer of energy from the pulsed high voltage generator to the radiation generating device. The radiation-producing apparatus generates pulsed beams of electrons and X-rays. Each pulse of the beam has a time duration of about 100 nanoseconds or less.
In accordance with another aspect of the present invention, there is provided a method of deactivating microbial contamination wherein the pulse of electrons and X-rays generated by the radiation-producing apparatus are directed to a source of microbial contamination.
One advantage of the present invention is the provision of a radiation-producing apparatus that is light-weight and portable.
Another advantage of the present invention is the provision of a radiation-producing apparatus that has a high efficacy, wherein surfaces and thin paper products, such as envelopes, can be decontaminated in a fraction of a second.
Another advantage of the present invention is the provision of a radiation-producing apparatus that requires minimal shielding to protect workers.
Another advantage of the present invention is the provision of a radiation-producing apparatus wherein the emitted radiation, i.e., electron beams and X-rays, has a penetration depth comparable to the thickness of a piece of mail but attenuates rapidly when traveling farther through the air or other substances.
Still another advantage of the present invention is the provision of a radiation-producing apparatus that is modest in cost.
Still another advantage of the present invention is the provision of a radiation-producing apparatus capable of deactivating anthrax spores and other microbial contamination, including, but not limited to, bacteria, viruses, spores and prions.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.